The economic costs of marine debris are not just the direct and indirect costs of damage, but in considering policy options, costs are inherently linked to the benefits from marine debris control. Marine debris is an “avoidable cost” and prevention is cheaper than cure. The costs of direct damage from marine debris to other users in the marine economy are an externality and an economic loss and can be measured. Indirect damage requires more information on vectors and damage functions, enabling physical damage to be valued. The second use of costs is for remediation, which generally consider density dependence and the net benefits from cleanup. All this discourse has yet to really be gathered into a global approach to future policy action and economic priorities. The economics of prevention versus clean-up may stack up globally in theory, but the local municipality spends to clean up their beach. In the marine economy this translates into capital investment into beach cleaning equipment, as opposed to capital being directed to larger scale prevention schemes. Other eccentric proposals direct precious capital into unrealistic open ocean cleaning exercises that have unproven technical and economic viability. A Coasian approach to reducing marine debris is undermined by a lack of rights in the ocean. So what is the answer? And who wants it? Going forward, countries wanting to prevent marine debris entering the ocean require improved governance regimes and an investment framework where the capital required for prevention can be applied wisely. This will likely cost more than we think!

The cost to West Coast Communities of dealing with trash, reducing marine debris

Under contract to the United States Environmental Protection Agency (EPA) the Kier Associates team contacted a random sample of U.S. West Coast communities in California, Oregon and Washington located in watersheds which drain into the Pacific Ocean. Also included were data from 15 California cities collected in a separate, initial study begun at EPA in 2011. From the data received from these 90 different communities, which ranged in size from just over 200 residents (Ukiah, Oregon) to over 4 million residents (Los Angeles, California), the team found that, regardless of the distance from the ocean or the number of residents, West Coast communities are spending approximately $13 per resident per year to combat and clean up trash, much of which would otherwise end up as marine debris. Cost information was sought for six different activities related to trash management, namely: beach and waterway cleanup, street sweeping, installation of storm‐water capture devices,

storm drain cleaning and maintenance, manual cleanup of litter, and public anti‐littering campaigns. Extrapolated, these direct costs amount to more than one half billion dollars each year to combat litter and curtail marine debris.

This is the first study to assess the social costs of marine debris washed ashore and litter left behind by beach visitors along different European coasts. Three identical surveys were implemented at 6 beaches along the Mediterranean Sea in Greece, the Black Sea in Bulgaria and the North Sea in the Netherlands. Beach visitors are asked for their experiences with beach litter and their willingness to volunteer in beach clean-up programs and their willingness to pay (WTP) an entrance fee or increase in local tax to clean up marine litter. Significant differences are found between countries. Assessing how responsible beachgoers feel for beach litter they partly leave behind themselves and to what extent they are willing to pay for their clean-up compared to litter washed ashore provides important information for priority setting in coastal policy and management. Public perception was measured in terms of public annoyance and whether the presence of beach litter is a reason to not visit a beach. Cigarette butts were reported as the main marine litter type, followed by plastic bottles and plastic bags. The clean-up of the latter was valued highest by beach visitors, followed by glass bottles and cigarette butts. The estimated WTP welfare measures are used as indicators of the social costs of marine litter. Actual or potential clean-up costs can be directly compared to these estimates to assess the economic welfare effects of clean-up actions in a cost-benefit framework. Applying the same study design across 3 different countries provides furthermore important insight into the spatial distribution of the social costs of marine litter across European states and the extent to which these costs differ across locations depending on public perception of marine litter and socio-economic and demographic profiles of beach visitors.

Human pressure over coastal resources compromises the quality of the environment and threatens local coastal economies. Marine debris is the most conspicuous pollutant that makes beaches aesthetically unappealing to users. The perceptions and reactions of beach users to stranded litter were compared between second-home owners and users (SHOU) and non-recurrent tourists (T). Socio-economic characteristics; assessment of the overall beach quality and perception of beach litter pollution (perception); hypothetical scenarios of marine litter pollution and deterrence (reaction); and potential alternative destinations in the case of deterrence (economic effect) were obtained through a questionnaire. Questionnaires (n = 319) were applied at two Brazilian beaches, with different physiographical settings (Pontal do Sul, PS, estuarine beach; Ipanema, I, open-ocean beach). Beach users’ groups differed regarding daily expenses (T>SHOU), period of permanence per trip (SHOU>T) and trip frequency (SHOU>T). Marine debris generation was mainly attributed to local “beach users”, in the open-ocean beach (I). “Marine” (or nonlocal) sources were four times more frequently cited in the estuarine beach (PS). Perception on actual litter pollution and litter deterrence scenarios, did not vary between beaches or groups. More than 85% of beachgoers would avoid a beach visit if a worst scenario (> 15items/m2) occurred and most users would choose a neighboring state beach destination. Stranded litter may potentially reduce local tourism income by 39.1%, representing losses of up to US$ 8.5 million per year. These figures are proxies to support the trade-off local authority’s make between investments to prevent/remove beach litter and the potential reduction in income from a tourist destination change.

presenting: James DelBene (Virginia Institute of Marine Science at William and Mary, United States); authors: James DelBene (Virginia Institute of Marine Science at William and Mary, United States), Donna Bilkovic (Virginia Institute of Marine Science at William and Mary), Kirk Havens (Virginia Institute of Marine Science at William and Mary), Andrew Scheld (Virginia Institute of Marine Science at William and Mary)

The Chesapeake Bay blue crab Callinectes sapidus fishery is responsible for 35-50% of U.S. blue crab commercial harvests valued at $150-200 million annually. Crab traps are the primary commercial fishing gear used to harvest blue crabs, and it is estimated that 12-20% of approximately 600,000 licensed traps in the Chesapeake become derelict each year. Ghost fishing impacts on valued bycatch species are well documented, yet further analysis of derelict trap impacts on blue crab harvest is necessary to support a profitable and ecologically sustainable fishery. Analysis evaluating the 2008-2012 Marine Debris Location and Removal Program that employed watermen to remove derelict traps in the Chesapeake suggests removal of 10-15% of derelict traps increased harvest by 22 million pounds. To verify these findings, preliminary experimental data collected from the Mobjack Bay, VA, in 2017, analyzed blue crab harvest in a control group of actively fished traps (baited) without derelict traps (unbaited) present and a treatment group of actively fished traps with derelict traps present. Blue crab harvest was significantly lower in the treatment group where derelict traps were present. On average, 4.9 crabs per trap per day (SD = 2.7) were harvested from the control group, compared with 3.3 crabs per trap per day (SD = 2.0) harvested from the treatment group. This finding further supports the claim that derelict traps create an uncontrolled inefficiency in the blue crab fishery that decreases the harvest of blue crabs, requiring a larger investment of time and resources from watermen to reach harvest limits. Better understanding of derelict trap impacts informs management agencies on effective development and implementation of best management practices to ensure a sustainable and profitable fishery for all stakeholders.

While knowledge is continually advancing on the ecological impacts of marine debris, methods to evaluate the comparative scale of these impacts are less well developed. Understanding how the benefits of marine debris removal efforts relate to other types of restoration can allow resource managers to direct limited restoration funds to projects that produce the greatest gains in ecosystem services. We propose a framework for evaluating marine debris removal projects in an ecosystem service equivalency analysis framework and use it to evaluate the comparative benefits of past marine debris removal projects. By drawing on existing spatial and temporal data on the habitat (e.g. scouring) and resource (e.g. ghostfishing) impacts of marine debris, we demonstrate how a resource manager can quantify the ecosystem service benefits of a removal project in present value terms. We apply this framework to a sample of past NOAA-funded removal projects and rank them based on ecosystem service gains and cost-effectiveness.